﻿/*******************************************************************************
 * Copyright (c) 2007
 * Sergey Berezin, Dmitry Voitsekhovskiy
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms,
 * with or without modification, are permitted provided
 * that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * - Neither the name of the Moscow State University nor the names
 * of its contributors may be used to endorse or promote products
 * derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 * THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ******************************************************************************/
using System;
using System.Reflection;

namespace Faml
{
    public class TypeMatcher
    {
        private Type[] genArgs;
        private Type[] genValues;

        public TypeMatcher(Type[] genericArguments)
        {
            genArgs = genericArguments;
            genValues = new Type[genArgs.Length];
        }

        public Type[] ActualTypes
        {
            get
            {
                return genValues;
            }
        }

        public bool Match(ParameterInfo[] parameters, Type[] argTypes)
        {
            Type[] parTypes = new Type[parameters.Length];
            for (int i = 0; i < parameters.Length; i++)
                parTypes[i] = parameters[i].ParameterType;
            return Match(parTypes, argTypes);
        }

        public bool Match(Type[] parTypes, Type[] argTypes)
        {
            if (parTypes.Length != argTypes.Length)
                return false;
            for (int i = 0; i < parTypes.Length; i++)
                if (!Match(parTypes[i], argTypes[i]))
                    return false;
            return true;
        }

        public bool Match(Type parType, Type argType)
        {
            if (parType == argType)
                return true;
            if (parType.Name == argType.Name && parType.ContainsGenericParameters)
                return Match(parType.GetGenericArguments(),argType.GetGenericArguments());
            else if (parType.IsArray && argType.IsArray && parType.GetArrayRank() == argType.GetArrayRank())
                return Match(parType.GetElementType(), argType.GetElementType());
            else
            {
                int genIdx = LookupGenericType(parType);
                if (genIdx != -1)
                {
                    if (genValues[genIdx] == null)
                    {
                        genValues[genIdx] = argType;
                        return true;
                    }
                    else return (genValues[genIdx] == argType);
                }
            }
            return false;
        }

        private int LookupGenericType(Type type)
        {
            for (int j = 0; j < genArgs.Length; j++)
                if (genArgs[j] == type)
                    return j;
            return -1;
        }
    }
}